Helix-coil stability constants for the naturally occurring amino acids in water. XII. Asparagine parameters from random poly(hydroxybutylglutamine-co-L-asparagine)

The synthesis and characterization of water-soluble random copolymers containing L -asparagine with N⁵-(4-hydroxybutyl)-L -glutamine, and the thermally induced helix-coil transitions of these copolymers in water, are described. The incorporation of L -asparagine was found to decrease the helix content of the polymers in water at all temperatures. The Zimm-Bragg parameters σ and s for the helix-coil transition in poly(L -asparagine) in water were deduced from an analysis of the copolymer melting curves in the manner described in earlier papers. The computed values of s indicate that asparagine destabilizes helical sequences at all temperatures in the range 0–60°C.